title: Inhibition of Delta1 promotes differentiation of odontoblasts and inhibits proliferation of human dental pulp stem cell in vitro.
abstract: OBJECTIVE
  Dental pulp stem cells (DPSCs) have been receiving more attentions recently as an important biomaterial for tissue engineering. Notch signalling plays a key role in regulating self-renewal and differentiation of a variety of cells. The objective of this study is to investigate the effects of Notch-Delta1 RNA interference (RNAi) on the proliferation and differentiation of human dental pulp stem cells in vitro.
  
  
  METHODS
  In the present study, we performed gene knockdown of Notch ligand Delta1 in DPSCs using lentivirus-mediated Delta1-RNAi. Changes of proliferation in DPSCs/Delta1-RNAi were examined by cell cycle analysis, Cell viability assay (CCK-8) and Western blot analysis of proliferating cell nuclear antigen (PCNA). Cells were cultured in odontoblast differentiation-inducing medium, and the differentiation of cells was detected with Alkaline phosphatase ALP activity assay, Alizarin red S staining, calcium concentration measurement, and Western blot analysis of Dentine sialophosphoprotein (DSPP).
  
  
  RESULTS
  Lentivirus-mediated Delta1-RNAi stably knocked-down the expression of Delta1 and Notch signalling, and some of DPSCs/Delta1-RNAi displayed changes in morphology or DSPP expression. The growth rate of Delta1-deficient DPSCs was significantly suppressed as compared with wild type DPSCs and control lentivirus vector transfected DPSCs. Furthermore, the differentiating capability of DPSCs/Delta1-RNAi into odontoblasts is much higher than the two control groups.
  
  
  CONCLUSIONS
  Notch signalling plays a crucial role in regulating self-renewal and differentiation in DPSCs. The deficient Notch signalling inhibits the self-renewal capacity of DPSCs and tends to induce DPSCs differentiation under odontoblast differentiation-inducing conditions. These findings suggested that DPSCs/Delta1-RNAi might be applicable to stem cell therapies and tooth tissue engineering.
authors.affiliation: Department of Stomatology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, PR China.
authors.forename: Xuefei
authors.initials: X
authors.lastname: Wang
authors.forename: Fei
authors.initials: F
authors.lastname: He
authors.forename: Yinghui
authors.initials: Y
authors.lastname: Tan
authors.forename: Weidong
authors.initials: W
authors.lastname: Tian
authors.forename: Songbo
authors.initials: S
authors.lastname: Qiu
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000704:Analysis of Variance; D002454:Cell Differentiation; D049109:Cell Proliferation; D002470:Cell Survival; D002478:Cells, Cultured; D003782:Dental Pulp / Q000166:cytology*; D023381:Endpoint Determination; D016326:Extracellular Matrix Proteins / Q000096:biosynthesis; D055785:Gene Knockdown Techniques; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D008565:Membrane Proteins / Q000037:antagonists & inhibitors / Q000502:physiology*; D009804:Odontoblasts / Q000166:cytology*; D010750:Phosphoproteins / Q000096:biosynthesis; D018809:Proliferating Cell Nuclear Antigen / Q000096:biosynthesis; D034622:RNA Interference; D051880:Receptors, Notch / Q000502:physiology*; D012795:Sialoglycoproteins / Q000096:biosynthesis; D015398:Signal Transduction; D012844:Sincalide / Q000502:physiology; D013234:Stem Cells / Q000166:cytology / Q000502:physiology*; D000099311:Dentin Sialophosphoprotein
chemical_list: D000469:Alkaline Phosphatase; D016326:Extracellular Matrix Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D010750:Phosphoproteins; D018809:Proliferating Cell Nuclear Antigen; D051880:Receptors, Notch; D012795:Sialoglycoproteins; D012844:Sincalide; D000099311:Dentin Sialophosphoprotein; C064045:delta protein